The simian core will be responsible for all monkey manipulations and the SIV virology. As such, it provides the necessary reagents required for the accomplishment of the aims of all the projects in this proposal. This core will obtain monkeys, infect them with a titered stock of HIV/DeltaB670, administered treatment with PMPA, and immunize with the vaccines provided by projects 1 and 2 according to the proposed schedule. Monkeys will be followed for signals of immunodeficiency by clinical examination, enumeration of T cell subsets, and quantitation of plasma virus loads. The results of these assays will be organized in a computer database using Blacksmith software and a Sun sparkstation networked to the project laboratories for ready access. This core will provide for the clinical care of monkeys on this project and will be responsible for the collection and distribution of blood, lymph node, and bone marrow samples to the other projects as needed. Monkeys in end-stage disease or at the termination of the experiment will be humanely sacrificed and tissues collected and distributed to project laboratories for analysis.